Fireborn

This is the second title in Toby Forward's "Flaxfield" quartet. When an old, dying wizard steals magic from his young apprentice, Bee, he changes his own life and nearly destroys hers. But he also releases Wild Magic into the world. Flaxfield and his apprentice, young Cabbage, set out to rescue Bee and make sure the old wizard doesn't use the Wild Magic against them all.